Steam ejector with cooled diffuser



A. DELAS STEAM EJECT OR'WITH COOLED DIFFUSER March 13, 1928.

Filed 09*, 31, 1918 '6 van *0 %M;/ bg iiawbznog a wag, W

Patented Mar. 13, 1928.

UNITED fi'iA'lES PATENT O FFlQE.

restate ALBERT DELAS, F PARIS, FRANCE.

STEAM EJECTOR \VI'IH COOLED DIFFUSER.

Application filed October 31, 1918, SerialNo. 260,6011}, and in France September 6, 1918.

In the construction of ejec-tors of a high ratio of compression it has heretofore been the practice to give the diffuser a conver gentdivergent form. This form however, is

only suitable when the normal ratio of com pression has been attained, as the starting operation is very diflicult. It is difiicult to start because the density of the fluid in the nozzle chamber is much higher than that which must prevail under normal operation.

Consequently, the jet of steam which is employed as the motive fluid, not only spreads out but loses a. part of its speed by virtue oi this denser atmosphere, and for a pr edetermined surface the weight of the fluld that it carries along 1s considerably 1n- (1'@dS8l, due to the high density of this fluid.

lllhoretore, it the distance from the nozzle to the neck of the diffuser has been calculated and proportioned for the maximum e'fiiciency under normal operation the jet of steam will strike the inside wall of the ditluser and the ejector will not start. For the some reason the vacuum will fall down (technically known as upsetting) if, during iorinal operation, some abnormal quantity of tluid rushes in. In order to avoid these dilliculties the various builders, up tothe present time, have been obliged to construct weight of the fluid to be extracted, and not for normal operation. Also the diffuser in general has been constructed more open,

than would otherwise be required, in order 7, the the steam, which spreads out at starting. should not touch its inner wall.

'i he apparatuses just described have an important bearing on the normal operation because. it the neck of the diffuser is too large for normal operation, the fluid coluo forced into the diiluser will have a. contracted section which is smaller than the neck of the diffuser and will therefore not lit the sides of the di'lii'user; and from the moment that the fluid column leaves said :i' es eddies will be formed which interfere with the output and with the stability of the ejector. To overcome this builders have been obliged to admit extraneous air or c-thcr fluid into the diffuser in order that the latter may always be filled, thereby pre venting the column from expanding and thus giving rise to eddies. The loss of chiicy due to the work necessary to comp.. s this air or other fluid admitted is consiterable but necessary to stabilize the .13 the neck or? the difiuser for the maximum.

apparatus. But it is obvious that the maximum of efiioiency with such an apparatus is obtained only at thev moment of starting and for the poor vacuum. After having used it exclusively certain builders have given up this process of stabilization as too costly and sacrifice both the efficiency and the stability by employing some intermediary metho j Furthermore, in order to allow the starting in certain types of apparatus, it has been necessary to use several nozzles, instead of one, and to reduce the total surface according to the laws governing the quantiies of movement under normaloperation. his again sacrificesthe efiiciency, andthe use of several nozzles necessitates an extreme reduction in the dimensions of the neck of the nozzles-few tenths of, a millimeter. desirable characteristic; that is, they are frequently obstructed because of some unfiltered deposits carried along by the motive fluid.

It may therefore be briefly stated that, among others, attempts to stabilize ejectors, the ratio of compression of which are Those nozzles introduce another unnecessarily subject to fluctuations, have been i made eitherby providing air inlets at the throat ot the dittuser or in thespace in which the vacuum is maintained, or by varying the cross-sectional area of the throat of the diii'user, either automatically o otherwise in accordance with the ratio of compression, ,and by varying the amount of motive fluid admitted.

My present inventionis an improvement upon my Patent No. 1,37l,990 dated April l9, 1921, the object being to more effectively insure automatic stability, irrespective of the ratio of compression, without admitting air, without varying the amount of working steam, and without varying the cross sectional areaoi the throat. p

An ejector constructed along-conventional lines was equipped with a cooling means and tested out. As compared with a similar device, where the cooling was carried on at the divergent portion only, very little difference in effect could be noticed. T hlS leads to he conclusion that it is useless,'trom a practical standpoint, to provide the divergent when the angleot divergence decreased,

till

drical forms, this form ha ing the advantages of being easy to construct and greater Stability in the producturn of higher *acuums.

It is a matter of common knowledge that the steam issuing from the nozzles. during the production 01? high vacuums. has the shape of a cone the length o t which iI]Cl' t.S(' in proportion to the reduction of the pressure. Consequently, the neck of the steam jetdisplaces itself dowawardly with re terence to the neck of the ditluser. It in this displacement the cross sectional arei of this shitting neck can be u'iaintained constant the equilibrium or .stabilit v will likewise be nniintained, and to accomplish this the usual diverginp portion is made cylindrical. or si1bstantial s-o. And with this explanation it wilt now be obv ous to those tilled in this art. that in the pro: action of higher vacuums a greater stability is assured. In the ordinary form of ditluser the diaplacement oi. the neck of the steam jet etlect:--' an iner ase in its cross-sectional area with a result of "upsetting of the device became the momentum per unit of surface being reduced; or in any case there will result detrimental pulsations. Furthermore I have found, when the usual divergent portion it? made of cylindrical form. that the ability of the device to extract a fluid is not. impaired in the least.

I have therefore found that the anele ot divergence of the dilluser may be reduced since the cold wall cr inpeni-alez-" tor the lack of divergence by condensing a certain amount oi tluid. For this reason it becomes possible to reduce the angle of divergence to zero, that is to say. it enables the substitution of a cylindrical pipe with cooled \valh; for the ordinary form of the diverging portion of a dilt'ueer. This will in no way impair the etlicieney, and it enables the throat to shift. over the entire cylindrical length. at the same time imparting great stability to the apparatus and greatly facilitating itz: construction. The angle of divergence may even be made negative. that: is. the ordinary divergent portion of the dill'user may be. made convergent. This type ot ejector may be readily adapted to all cases, more particularly in the case where two or more steam cjectors are separated by one or more intermediate condeueers, a ver advautageousiy arranged apparatus is secured. The circulating water, which has been employed to cool the wall of the upper diffuser may by means of holes provided in the wall, be made to enter said dittuser for the purpose of con- (lensing the steam coming from the upper ejector and lie returned to the main rondens er or removed by suitable means.

Although no claim is made to nnihi--ta;'e ejector syiitenn in the pie-cutv applicatimi this SIllJJCCt-Hltll'ttl in claim d in my opending applications Serial :itlr. 321.311 and 396. 018.

The annexed drawing rhows, by way o. (-xanipl' and in axial set-lion. one ol' the elements of my improved cit-"tor and it:- intermediate condenser.

The reference letter u. desie'uat i a nozzl only one being; illustrated. but it obvious that a plurality of the rum" may be employed. However. the automatic martini: etl'ected by the s-yetem which torm= the rubjert matter of my patent abow relerrt l t tlltllJltl'ri the use of a tlllff'lt nozzle white at the ;-1ame time preserving- '1 large rtl' tive area. The converging" )Ul'lltlll ot' the iillueer is illu-tiratcd at [1. while the ditl'uo-r p rtion it; illu l 'ated at r. the latter. in th lorm of th d vice shown. com1n'i.--,in;2' a cylindrical pipe. The throat i located at 'l'h entire dill'us r is tilllzttllltlt'tl by 1: ca inc and it it between i'hhcasing and the wall of the dill'uswr that the. cooling: medium is adapted to circulate.

The valls in contact with the \vorlciu tr or motive thud, and more 1: rtieulwrly thow t-l" the nozzle and dill'user, ar prel'e; ably ni k lplated. in whole or in part, in order. primarilv, to minimize the friction of the tluid. A very Simple method of oinir f i llif the. walls consii-ls in producing' them el lytic means, for example; by a ltlh'yfl copper upon a mold in a bath, 1 h by the same means. bein; sub wpi ni red with nickel at the point when coating is desired. 'lhie. meihml of H1. iat'atture admih of ready lltl"l' il;lll 't' of h at through the walls.

\Yhen the j tor i1 eomblnel with a ndenser it is furthermore provided with holwi in the section ot' the d v; .7. )1 port n corre-qnnnlingipraeticz lly to a pin: where the rctpiirvd prewure prevaili-c t'or d-livcry into the iutermwliate cr-nden-er o. I hohm 1'1. providrl in pipe r'. owin to i' relative. vacuum prevailing: in the !t])l,)ltltiti-. enables the cir ulating wat r. whi'xli bu be n llr-t l to cool th dill'u-er and whi h mph r higher preuure to inter th ini' ri r. nine at thiicrow wet ion the pipe (the inlet tube. maybe made convergent. lit: raw-n1 or cylindrical.

ltv in also [)Or-Edlllt to brain lhe inj tion ot water at a point upward trout raid 'tl'litlll Sui-h injection may even beain at the throat. of the divergent portion in order to complete by mixture the condemation on the sur'taciformed by the cooled rail of th ditl'lre In -ert:iin special cases such (OlifleIL-itltlfifl by injection is capable ol' being employed alone. In any event, the water condenses the steam so that at the discharge ofthe pipe 0 into the intermediate condenser there is practically only the ejected fluid and water, to the exclusionot all steam.

The hot water is drawn oil through the pipe j and the air through the pipe 0 which is concentric with the steam pipe of the suc ceeding ejector.

The ditluser is located almost wholly in the intermediate condenser g in order to re duce the total bulk of the apparatus. On the other hand, the air drawn in through the inlet pipe ascends through its bypass in the direction oil the arrow which by-pass is formed by the tube prolonging the diffuser and the outer wall in which receives the cooling or condensing water, so that the air may be cooled by contact with it and so that the vapor which may not have completely condensed, may tinish its condensation.

The diituser is fixed at its upper part, but it passes freely through ring a. at its lower end so to enable it to expand freely and so that a stream of water may also be pro vided at this point over the entire periphery in order to accelerate the condensation.

From the foregoing descriotion it will be clear that I have not only designed an apiaratus but also provided a method by which the stability of an ejector is etlected for all conditions of normal and abnormal opera-i tion and also for the conditions which prevail 1n the starting ot the apparatus; and at the same time enabling a maximum eiticiency of the apparatus when operating under nor mal conditions of working. it will also be apparei nt that I have made provisions in the same apparatus and method ior completing" or practically completing the condensation of the uncondensed vapors flowing into the i iitermediate condenser.

What I claim is 1. In an ejector. the combination oi a nozzle for the motive fluid. an inlet tor the fluid to be exhausted. a ditl'user provided with a converging portion, a neck portion and an outlet port-ion, the inlet oi said couverging portion having a cross sectional area greater than that oi any other portion ot said diffuser and means compi' jacket surrounding all portio s of tuser for condensing the motive fluid which isin excess of working conditions requi ed,

in any portion of the diffuser.

2.111 an ejector, the combination oi" a nozzle tor the motive fluid, an inlet for the fluid to be exhausted, a ditluser provided with a converging portion, a neck portion and an outlet portion, the inlet of said conve ing portion having across sectional a greater than that of any other portion of said diffuser and means comprising a cooling jacket surrounding all portions of said 'fiiser at a relatively low temperat diffuser for condensing anyeddies in the diffuser in the operation or the same.

3. An ejector ot a high ratio of compression comprising a diffuser having a converging inlet portion, a neck portion, and an outlet portionwhose maximum cross-section is substantially the same as that oi said neck portion, and a cooling means for all portions otthe diffuser. v

4:. An ejector ot a high ratio of compres sion comprisinga diii'user having an outlet portion of substantially cylindrical form to maintain the neck portion of the steam jet constant as it shifts in the production of high vacuums, in combination with cooling means for said portion.

5. An ejector of a hip sion comprising a diffuser having portion of usual form and an outlet portion of substantially cylindrical form for the purpose described, in combination with cooling means for said portions.

6. An ejector of high ratio of compression comprising a ditl'user having an inlet portion and neck portion of usual terms and an outletportion of substantially cylindrical term for the purpose described, in combination with cooling means for said inlet, neck and outletportions.

'4'. A construction of an ejector as defined in claim 5, in which provisions are made for cooling fluid to enter the outlet portionot the diffuser to further condense the motive fluid moving through the ejector.

8. The process of ejecting a fluid which consists in passing a motive fluid through a diffuser in a quantity sutticiont to provide tor the normal ratio oi? compression, maintainan inlet h ratio of compresing the cross-sectional area oi theneck portion oi the steam jet substantially constant as it shitts along; the ditluser, and condensing the excess motive tiuid passing; therethrough.

9. The process of ejecting a tiuid which con-- sists in passing a motive tluid through a ditl' user in a quantity sutlicient to provide for the normal ratio of compr "sion. maintaining the cross-sectional area of the neck portion of the steam jet substantially constant as it shifts along the ditluser, and maintaining the outlet portion of the diffuser at a relatively low temperature to condense any eddies or excess fluid passing therethroimh. 10. The process of ejecting a fluid which consists in passin a motive fluidthrough a diiiuser in a quantity Slli'lltlBi to provide for the normal ratio oi' compre. on, rnainta m the neck por ing the cross-sectional area of tion of the steam jet substantially con.

it shifts along the diltuser, and maintainingthe inlet and outlet portions ot the dif- :e to condense any eddies or excess fluid passing; therethrough.

lzli) ll. The process of ejecting a fluid which coi'isists in passing a motive fluid through a diffuser in a quantity sutlicient to provide for the normal ratio of compression. maintaining the cross-sectional area of the neck portion of the steam jet substantially constant as it shifts along the diti'usen and maintaining the inlet. neck and outlet portions of the dill'uaer at a relatively low temperature to condense any eddies or excess lluid passing: therctln'oug'h.

12. A process as delined in claim 9. comprising the additional step of admitting at; least a portion 0! the condensing fluid emploved into the outlet portion of the diti'user to further condeintc the motive tiuid moving through the ejector.

1 A construction of an ejector as defined in claim 6. in which provisions are made for coolinc tluid to enter the outlet portion of the ditl'user to further condense the motive tluid moving through the ejector.

let. it eonst'ructi m (ifl an ejector as defined in claim '1'. in which provisions are made for cooling tiuid to enter the outlet portion of the diti'user to further condense the motive fluid moving through the ejector.

15. A process as defined in claim 10, comprising the additional step of admitting: at least a portion of the condensing fluid employed into the outlet portion of the diifuser to further condense the motive liuid moving through the ejector.

16. A process as defined in claim 11, com.- prising the additional step of admitting: at least a. portion of the condensing fluid employed into the outlet portion of the dill'user to further condense the motive fluid moving, through the ejector.

IT. A process as delined in claim 12, coinprising the additional step of admitting, at least a portion of the condensing tluid emplojrcd into the outlet portion of the ditl'user to further condense the motive fluid moving through the ejector.

19. An ejector eom uising in combination, a tuhular ditl user. a. cooling jacket for said diii'u er. and a casing surrounding said diti'uecr and jacket.

19. An ejector comprising: in comhinatimi, a diti'uscr, a sleeve surrounding said ditiuser, inlet means for supplying cooling fluid to the interior of said sleeve and exit means tor said tiuid. and a casing surroinuling raid sleeve.

in. An ejector comprising in comhinat irm, a casing, a. tubular difi'uscr extending; into said casing, means connecting said diffuser and using but permitting relative movement of the same upon variation in temperature and means for passing cooling fluid through said casing in contact with the exterior ol said diti'user.

21. An ejector comprising, in combination, a casing, a difl'user extending into said casinc, means connecting said diti'nser and casing' hut permittingg relative movement of the same upon 'ariation in temperature, sleeve surrcuinding said diiluser, and means for passion cooling fluid through said casing lHiWtPtlil said ditluscr and sleeve.

552. An ejector comprii-iire in coruhinatimi. a casing, a tuluilar diil'iner lined thereto at one end but capahie of" movenuuit with respect thereto at it: other end. :aid casing" surrounding said ditl'u cr. and mean for supplying elm-tic motive tlu l to raid dih iuser.

23. Au ejector t"|wl)!'l-lllff in c unhination, a tuhular dili'trer. a (:ilillllthltfl' hau'iher iu illllllliilt'tlii il with one wad oi raid dill'uecr. a. sleeve urrounding lilll d tl'nwr closely adjacent thereto. means for :uppl viu r a current or" cooling lluid to the interior of said sleeve. and a ca-ing. surrounding :aid sleeve.

Ll. An air and non-condor F'tiblt! fluid ejector tor a stcampoivcr-plant condenser wherein a luv: alaoiute or h ghl *acuous pressure inirniall obtains comprising a chamher adapted for communication with apparatus oif the character designated, a diil'u:-'er communicatinc with the chamber, an expanding nozzle o." the divergent type for transforming: steam at high pressure into steam haviuo; loiv ahsolute or highly vacuus pressure and movingat high velocity and f r discharging the high-velocity steam in a jet across at least a portion ot the space oi said chainher and into said diiluscr, the high velocity jet entraining air and noncoinlensahle lluids trom said chamhcr and the mixture oil. steam. iii and non-condensahle tluids und. rgroingr velocit v-pressure conversion in the dill'uscr. and means co-opcrating with tho ditl'nser. including the con verging; portion thereot. l'or condensing Hich part of the steam of the mixture that the volume ol' :1 given mass of mixture does not, increase in its pumice through the major portion ol? said dill user in order to improve the performance ol' the ejector.

25. An air and nonomlensahle fluid j tor for a. FtQlillll)O\\'t3l'-l)ltllll' comlen.-=er where in a. low ahsolute or l1l; "lll Y racuous pressure normally ohtains comprising a haiuhcr adapted for ommuni ation with apparatus of the character itcll ll'litllwl. a dili'urcr c mmunicating with the ehamhcr. an mcpandiug; nozzle of the divergent, t vpe tor trauwhnaw ing steam at high pre snre into steam having low ahsolute or highly vacuum pre suriand moving at high velocity for dist-harps 115! the high-velocity steam n a jet a roi-ai at least a portion ot the space ol said hainher and into said dilluser. the high rclocitv jet ent aining air and noucomleu. alilc fluids from said chamber and the mixture of steam, air and non-condcnsahlc fluids uudera'oing velocity-pressure ccmversion in the diti'user,

and means co-operating with the difluser, including converging, diverging and throat portions thereof, in order to condense such a portion of the steam oi the mixture that the volume of a given mass of mixture does not increase in its passage through the major portion of said di'tiuser to improve the performance of the ejector.

26. An air and non-condensable fluid ejector tor a steam-pow in a low absolute or highly \acuous pressure normally obtains comprising a chamber adapted for communication with apparatus of the character designated, a diti'user comn'iunicating with the chan'iber, an expanding nozzle of the divergent type for transforming steam at high pressure into steam having low absolute or highly vacuous pressure and moving at high velocity and for discharging the high-velocity steam in a jet across at least a portion of the space of said chamber and into said diiiuser, the high velocity jet entraining air and non-condensable fluids from said chamber and the mixture oi steam, air and non-condensable fluids undergoing velocity-pressure conversion in the difl'user, and means co-operating with the difl'user for eliecting condensation of such part of the steam of the mixture throughout the length of the difluser that the volume of a given mass of mixture does not increase in its passage through the major portion of said difluser in order to improve the performance of the ejector.

27. The process of ejecting a fluid which comprises passing an elastic motive fluid though an elastic fluid to be ejected to entrain said fluid passing the mixture through a diffuser and progressively cooling saidmixture so that the volume of a given mass thereof at any point in said difluser does not exceed the volume of said mass at a preceding point in its path through said difluser.

28. The process of ejecting a fluid which comprises expanding an elastic motive fluid in contact with a second elastic fluid to be ejected, to entrain said fluid,,and passing the mixture through a diffuser, and progressively cooling said mixture during its progress along said difluser so that the volume of a given mass of said mixture is a maximum at the inlet of said diffuser.

29. The process of ejecting a fluid which comprises expanding steam in contact with the fluid to be ejected, to entrain said fluid, and passing the mixture through a difl'user, while regulating the temperature of said mixture during its progress through the diffuser, at such value that the volume of a given mass of mixture therein does not increase.

30. The process of ejecting a fluid which plant condenserwhere comprises expanding steam in contact with the fluid to be ejected to entrain said fluid,

passing themixture through a difluser, and

progressively condensing such quantities of steam that the volume of a given mass of mixture never exceeds the volume of said mass at the inlet to said diffuser.

31. In an ejector, in combination, a casing, an inlet in said casing for motive fluid, a second inlet for fluid to be ejected, and a diltuser the cross sectional area of which is a maximum at the inlet thereof.

, In an ejector, in combination, a casing, an inlet in said casing for motive fluid, a second inlet in said casing for fluid to be ejected, and a diffuser, the cross sectional area of said diii'user being no greater at any point therein than the cross-sectional area of any section between said point and the inlet thereoit.

33. In an e ector, in combination, a casing, an inlet in said casing for motive fluid,

a second inlet for fluid to be ejected, and a difl'user, said difluse'r being mounted in said casing at one point only in the length thereof.

34. In an ejector, in combination, a casing, an inlet in said casing for motive fluid,

a second inlet for fluid to be ejected, and a. diffuser, said difluser being mounted in said fuser mounted in said casing by the inlet end only and out of contact with saidcasing at other polnts, and a chamber for cooling liquid surrounding said difl'user, the bottom wall of said chamber being formed to pro vide for a flow of cooling liquid from said chamber about the end of said diffuser.

37. In an ejector, in combination, a casing, an inlet in said casing for motive fluid, a second inlet for fluid to be ejected, a diffuser mounted in said casing by the inlet end only and out of contact with said casing at other points, and a chamber for cooling liquid surrounding said difl'usenthe bottom wall of said chamber being provided with an opening, and the outlet. of said diffuser projecting therethrough.

In witness whereof I have hereunto signed my name.

ALBERT DELAS. 

